Triangle read by rows: T(n, m) = (n+1-m)*C(2*n+2-m, m)*C(3*n-3*m+2, n-m+1)/(2*n-m+2).

Terms

a(0) =1a(1) =5a(2) =2a(3) =28a(4) =20a(5) =3a(6) =165a(7) =168a(8) =50a(9) =4a(10) =1001a(11) =1320a(12) =588a(13) =100a(14) =5a(15) =6188a(16) =10010a(17) =5940a(18) =1568a(19) =175a(20) =6a(21) =38760a(22) =74256a(23) =55055a(24) =19800a(25) =3528a(26) =280a(27) =7a(28) =245157a(29) =542640